EM78M611E
Universal Serial Bus Series Microcontroller
28 •
••
•
Product Specification (V1.1) 11.22.2006
(This specification is subject to change without further notice)
After the PDA function is enabled (by setting IOCA[2] to 1), user can write a default
value to the High Pattern counter register and Low Pattern counter register. Then set
the corresponding interrupt enable bit (IOCF[5]). When the counting value of one “H”
pattern is bigger than the default value of R11, the Pattern Detecting interrupt will be
generated. Similarly, if the counting value of one “L” pattern is bigger than the default
value of R10, Low Pattern Detecting interrupt will occur. Thus, the EM78M611 is
notified and aware that one effective pattern is received from P.92.
If user does not need these two interrupts, they can be masked. The new value of
counting a pattern will still be loaded to the R10 and R11. The firmware must poll and
determine whether the value of these two registers has changed or not.
8.10 Pulse Width Modulation (PWM)

8.10.1 Function Description

In PWM mode, both PWM1 (P.92) and PWM2 (P.93) produce plus programmable
signal of up to 8 bits resolution.
The PWM Period is defined as 0xFF × Timer Counter Clock. The Timer Counter clock
source is controlled by an extra control register, ERE. For example; if the Clock source
is 1MHz, then the Period will be 255 µseconds.
Period = 255 × (1/Timer Counter Clock)
Period (0xFF * Clock)
Duty Cycle
Fig. 8-2 The PWM Output Timing

8.10.2 Duty Cycle

The PWM duty cycle is defined by writing to the R10/R11 Register for PWM1/PWM2.
Duty Cycle = ( R10 / 255 ) × 100% for PWM1
( R11 / 255 ) × 100% for PWM2

8.10.3 Control Register

R10 (PWM1 Duty Cycle Register)
A specified value keeps the output of PWM1 to remain at high for a Period.
R11 (PWM2 Duty Cycle Register)
A specified value keeps the output of PWM2 to remain at high for a Period.
ERE(PWM Control Register) Default Value: (0B_0000_0001)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
PEN2 PEN1 - - - PS2 PS1 PS0